SIMPLE AND ECOLOGICAL OBTENTION OF CHITIN FROM CRUSTACEAN WASTE

Abstract

Crustacean farming generates large quantities of residue, posing environmental and economic problems. These residues contain chitin, proteins and a carotenoid pigment, all of high commercial value, and wide applicability. These compounds are associated with each other in a complex biological counterfoil, rich in calcium carbonate. The available extraction methods for shrimp residues are slow and burdensome, relying upon thermal treatments with concentrated acids and bases, or fermentative methods with high costs in energy, water volume and chemical products. We present here different assays, which were performed to develop an economical process which is environmentally friendly, with acceptable yield, comprising two brief and consecutive steps. The best condition tested was: demineralization with citric acid (ratio weight of residue: citric acid =5.5) for 20 min. at 40ºC, followed by deproteinization with pancreatic enzymes in 0.5 M ammonium citrate buffer at 40ºC. More than 80% of the raw chitin was recovered (4% minerals, 8% protein and 21% carotenoids remnant content), while 70% of the total proteins and 60% of the total carotenoids remained in the final filtrate. Discoloration of the raw chitin was easily performed with acetone.